Processing chambers are known for processing food products, pottery, metal products, and the like under conditions established in such a chamber. Conveyors are used for conveying such products either continuously or in batches through such chambers. In many cases, it is desirable to establish a chamber with a series of different zones, in which different conditions exist.
This is particularly desirable in the processing of food products such as meat, poultry, and processed meat such as hams, picnics, pork bellies, luncheon meats and sausage.
In these cases, different zones may provide for air circulation, or water shower or water spray treatments. The air may be either at an elevated temperature or contain smoke or other treatments, or may be at reduced temperature for chilling. Similarly, the water shower may be at an elevated temperature for cooking, or at a reduced temperature for chilling.
The atmosphere in the chamber may be tempered or modified by regulating the humidity, or by adding artificial smoke.
In the past, it has been usual to provide such chambers in which the products were moved gradually and progressively and continuously through the various zones in the chamber by a continuously moving conveyor.
In these cases, however, it was necessary to operate the chamber at preset conditions in the various zones, and since the products were moving continuously through all the zones at the same speed, it was only possible to process one type of product at any given time.
In order to change products, it was necessary for the product already in the chamber to be completely processed all the way through which might take several hours, and then, when the chamber was empty, the conditions could be changed, or the speed of the conveyor could be changed, to suit a different product.
This type of installation involved a very substantial investment in capital. It was therefore suitable only for processing products in very large volumes.
It also produced a considerable degree of inflexibility in the use of the equipment. Clearly, it is desirable to provide a processing chamber at a lower capital cost which is capable of processing various different products,for different dwell times, and in which the conditions may be changed more readily, and more frequently.
One way in which this may be achieved is by providing a processing chamber in which the conveyor does not move continuously throughout the chamber, but in which it moves in a step-wise fashion, progressively moving individual batches or units of products through the chamber.
Since the batches or units of product will remain stationary, between the step-wise sequence of movement, the chamber can be made much shorter.
In this way,a substantial saving in capital cost is obtained.
However, it is still true that even with this modification, the chamber cannot be switched over from processing of one type of product to another until the first type of product has passed completely through the chamber.
Since this may take a considerable time, it means that a substantial delay may be created, by changing over from processing one product to the processing of another.
Accordingly, it is desirable, if possible, to provide for such a chamber in which there are two separate step-wise conveyor systems. In this way, a first batch or unit of product may be moved by one conveyor at a first speed and, as soon as a first zone of the chamber is free of such first batch of product, then a second batch of a different product may be moved into the first zone by a second conveyor, moving it in steps in a different sequence.
In this way, provided the two different products may be processed under the same processing conditions within the various zones, it is possible to process a first batch of one type of product followed by a second batch of another type of product, with very little down time in the use of the chamber itself.
Conversely where it is desired to change process conditions for a batch of different product, it is desirable to be able to change conditions in a first zone, and introduce a batch of a second product, while a batch, or batches of a first product are still being processed in a subsequent zone.
This means that with a lower capital cost, a small or medium sized processor, may process a variety of different types of product through the chamber, with a greatly reduced or minimized down time being created by the changeover from one product to another.